Using Topographical Maps
Carrying topographical maps, a gps, or compass is not enough. You need to know how to use them!
The wide-open terrain of the desert is especially inviting for someone who wants the extra adventure of hiking "off trail". We like to think of it as the "shunpiking" of hiking. (Avoiding the major routes.) But getting lost in the desert is a life-threatening serious situation.
All off-trail hiking poses extra hazards and even an experienced desert hiker needs to carry a compass, topo map of the area or a GPS with built in tracking features for hiking.
Lynn Altierineed provides some basic instructions to help you read the lines and symbols on these maps in her article titled, "Understanding A Topographical Map When In The Backcountry Is A Matter Of Survival."
There are multiple symbols, types of scales that are indicated on topographical maps that can be confusing. Here is an overview of what to expect with a topo map and useful information to make your nature experience a safe one.
Topographical maps give details to your location in relation to the equator, by using latitude and longitudinal lines with numbers located along the sides of the map. By cross-referencing you can identify where exactly you are located and also where you want to be. A topo map also features symbols which are mostly detailed in the scales area on the map.
All topo maps features a map scale which details a ratio scale and a graphic scale.
The first number on the ratio scale is how many inches will equal the second number of inches. For example, 1:25,000 means that one inch equals 25,000 inches on the ground.
The graphic scale usually shows a numerical scale in feet to be used to identify fast estimates of distances on the map.
Lastly, there will be a scale that shows distance in miles or kilometers for generalizing distances on the topographical map. A huge benefit of topographical maps is the three dimensional perspective displayed by using contour lines. A contour line is a line that connects two points of equal elevation. The term "contour interval" determines how many feet separate each contour line and can be found under the map scale.
Multiple contour lines appear all over the topo map but will never overlap. Circular lines represent a mountain peak. Each line outside of the peaks represents a decrease in elevation. For example if the contour interval is 80 feet and one contour line shows 10,800 feet then the line next to it (descending from the highest point) would indicate that the elevation is 10,720 feet.
NOTE: Magnetic declination is a scale that shows you per topo map where magnetic north is in position to geographical north on your map. Magnetic north is necessary when using your map in conjunction with a compass.
A compass is a necessary part of survival gear and requires learning the application process and practice. Please refer to a compass and its user guide for specifics. Altimeter watches can incorporate a compass and an altitude detector but should also be used in conjunction with a topo map.
A geographical positioning system such as the GPS Garmin or the GPS Rino can offer all of the benefits (and even more) of a topo map. However always include a hard copy topo map. Nature doesn't care about technology.
Author
Lynn Altierineed
So there you have the basics on using topo maps.
My desert hiking page will give you some other unique route finding tips (some of which, we pioneered) that could save your life.
Whether you're a seasoned hiker or new to the desert, having and knowing how to read a topo map will give you the added confidence you need to explore just a little bit farther. Going places where, perhaps, no man has set foot for decades. And that, for us, is the real allure of off-trail hiking.
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